Post-black or post-black/shoegaze type stuff yeah. Some other bands have some similar styles. Wolves in the Throne Room has some stuff that's kinda like Agalloch, also Lantlos, Heretoir, Grauzeit, Old Silver Key, Mortifera and to some extent Paysage d'Hiver, Verdunkeln, Void, Thranenkind, etc... (If you haven't noticed I'm big into the German scene :P)

When you say Agalloch, I'm guessing you're referring to bands with nature themes and with atmospheric sound, some bands of the Cascadian scene for example (aka: Atmospheric BM) have a similar sound to Agalloch, that may interest you, some atmospheric: